/Engine/Plugins/Online/OnlineServices/Source/OnlineServicesInterface/Public/Online/Lobbies.h
Get the event that is triggered when a lobby member joins. This will happen as a result of creating or joining a lobby for local users, and will trigger when a remote user joins.
Event that can be bound to
[TOnlineEvent](API\Plugins\OnlineServicesInterface\Online\TOnlineEvent)< void(const [FLobbyMemberJoined](API\Plugins\OnlineServicesInterface\Online\FLobbyMemberJoined) &)> OnLobbyMemberJoined()